Idler bearing seal



June 9, 1953 w. F. BANKAUF ET AL 2,641,515

IDLER BEARING SEAL Filed sept. 20,'1950 y Z i.

Arron/VEN Patented June 9, 1953 ."UNirErDr-z STATES PATENT o FFICE-f.

Y u IDLEaBEARINGsEAL William'RBankauf, East Paterson, William E.Herrmanm Maywood, and IIamilton M. Ross,

f Wortendyke, N. J., assignors to Hewett-'Robins Incorporated, Buffalo,N.YYl., -a corporation -ofjv New York Application'September 20,1950,/SerialN`o.1`85,81v4H b 'YIhis invention `relates, generally toidler pulleys of .the kind used to support conveyor belts and v'is inthe nature ofv an improvement on; the subject rlralgter of Patent No.2,207,790,dated July '16, The primary object of this invention is tomake better provision for sealingthe idler bearings against the escapeof lubricant and the entry of dust or the like.

The invention will be readily understood from. the following descriptionof the accompanying drawing,V which is a vertical section through thebearing'end'portion of an idlerpulley and its associated parts havingthe preferred form of the invention applied to it. f j Y 'As is commoninsuchV constructions, the idler pulley, generally designated I,ismounted for rotation on a stationary hollow shaft 2. The pulley langemember 3 incorporates a cylindrical hub casing 4 within which are'ananti-friction bearing and the components of the grease and dust seal. Asshown, a roller bearing having an inner race 5 and an outer race 6 islocated at the inner end of the hub casing. Surrounding the shaft is a'tubular casing 'I supported by a funnelshaped duct 8 which is clampedbetween the inner end of fthe hub casing and the outer bearing race 6.Mounted on lthe shaft within the hub casing and shown yasabutting theinner bearing race 5 is a collar 9 which is locked against movementrelatively to the shaft by a lock nut I and a set screw II carried bytheupper end of the shaft post I2 in which the collar is seated. The springI3 serves to take up wear in thebearing and grease is supplied to thebearing by way of tting I4, the hollow interior of shaft 2 and shafthole I5. All of these numbered components are or may be of the sameconstruction as those described in the said prior Patent No. 2,207,790.

At the inner or left-hand end of the bearing and clamped at its outermargin between race 6 and the hub casing is a gasket washer I6, 'therebeing clearance between the washer and the shaft to provide for thepassage of grease to lthe bearing.' At the outer or right-hand end ofthe bearing, the inner lrace is encircled by an` annular grease sealvelement I1. This element, which may be of vcork composition or thelike,4 has an outer diameter such that the periphery of the elementclosely engages the hub casing for rotation therewith. It will be notedthat there is clearance between the inner race and the grease sealelement affording free rotation of the grease seal element about theinner race.

On the inner end of collar 9, two spaced washer 3 Claims. (o1. 30S- 20)members I8, I9 are mounted.` These members are press-litted on thecollar or otherwisesecured to it, so as to become to alln intents andpurposes a part ofthe collar. These washer members, however,'are spacedfrom the; hub casing. Washer member I8 forms an abutment for engagementby grease seal element I1; and between the washer members thereis'located va second and similar grease seal'element 20;-which, likeelement' I 1, engages thehub casing-for-rotation with it but is clear ofthe collar. Y Y f- When grease is forced through the fitting I4,vitfinds its .way to the bearing through the` hollow interiorl of shaft 2and hole I5,. as above` mentioned, and then through the clearance spacebe. tween gasket washer IISv and the shaft; fand, the grease passesthrough the bearings and builds up pressure in-the limited space betweenthe bearing and element/I1, it tends to force that element into sealingengagement with washer member I8. Similarly, any grease getting pastthis seal under the pressure incident to rfillingthe bearing tends toforceelement 20 into sealing engagement with washer member I9, with. there y sult that the possibility of grease escaping during pressurefilling is remote.

On the outer or right-hand side of the described grease seals, a furtherseal is provided. This is primarily -a dustsealand in this preferredform consists of a unit made up of annular angle shaped vmembers ;2 I,22 press-fitted togetherV and clamping between themk a dust seal elementr23 of Afelt or the like.v The inwardly opening kU- sectioned'shellmadeup'of the elements 2I,22 is press-ttedinto the'hubv casing orotherwise secured for rotation with it, with the dust seal element 23 inrubbing engagement with collar 9.A

It will be understood that the described bearing and seal arrangement isduplicated at the other' end of the pulley; also that after the illusftrated bearing has been lled in the manner described, the'introductionof more grease'through fitting VIll'lls up the' interior ofshaft 2 andalso the space between the shaft-.and casing 1, by which pathsthe'grease is'then supplied to the similar bearing at theother end ofthepulley.

The-'described'arrangement is highly effective to prevent the' escape ofgrease while it isunder pressure during filling and minimize the escapeof grease after such pressure has been relieved and the pulley isrunning on the shaft. Several features of the construction contribute tothis latter aspect of the invention.

While the pulley is rotating, the funnel-shape of duct 8 tends to giverise to an outward flow of grease due to centrifugal action; that is tosay, both radially and axially ou-tward of the shaft. However, since thegasket washer is in sealing engagement with the hub casing, it restrainsany such flow and prevents the building up of undue grease pressuretending to force additional grease into the bea-ring and through theseal, particularly at the zone of maximum diameter of duct 8, where thecentrifugal action is greatest. u

It has also been found that -the amount f grease escaping from the sealis' dependent to some extent upon the amount oi grease permitted toaccumulate on the outer side of the' anti-friction bearing. In thisconnection, it will be noted that by virtue of the describedconstruction the amount of this surplus grease on the outer side of thebearing is held to a minimum, due to the fact that the grease sealelement ll substantially llls the space within the hub casing bounded bywasher I8 and the bearing itself.

In prior `seal constructions, it has' been found that escaping greasehas a tendency, due ite centrifugal action, to ivo-rk radially outwardly'over the surface of pulley flange 3 and, in some instances,- even reachthe conveyor belt riding on the pulley, which, of course, is highlyobjectionablel- Inthis instance, any such tendency is reduced by holdingto a minimum the radius at which any grease which does pass through theentire seal can einer'g from it. As will benoted, the dust seal shell2l, 22 is closely tted to and rotates with the hu'b 4casing and if anygrease at all escapes, itcan only emerge between the dustsealeler'iieni", 23 and the collare. v

Where the terms outer side and "inner side are used in the abovedescription land in the claiins to indicatevthe relative locations ofthe various components axially of the shaft, outer side is intended tomean o n the side toward the adjacent shaft end or to the right asviewed in the drawing and inner side is intended to `rriean n tiiesitieremote fram the adjacent shaft end or to the left as viewed inthedrawing. n

In the light of the foregoing, which will be understood to describe onlythe preferred form of the invention, the following is claimed:

l. A bearing seal for an idler of the kind including a pulley having acylindrical hub casing, a hollow shaft extending therethrough, anantifriction bearing between the casing and the shaft at the inner endof the casingvand a collar secured to the shaft and extending from thebearingto the outer end of the shaft, comprising an annular reas-e sealelement adjacent the outer end Vof the anti-friction bearing having itsouter periphery engaged with the hub `casing for rotation therewith; apair of spaced washer members secured to the collar with clearancebetween their outer peripheries and the hub casing, the inner of saidWasher mem-bers lying adjacent the outer surface of the grease sealelement; a second annular grease seal element located between the washermembers with its outer periphery engaged with the hub casing forrotation therewith; an annular shell of inwardly opening U-sec-tion, onthe outer a side of said washer members, encircling but spaced from thecollar and secured to the hub casing for rotation therewith; an annulardust seal element clamped in said shell with its inner peripheryengaging the collar; and a gasket washer eneircling but Spad froi'n theshaft on the inner side of the bearing', the outer periphery of saidgasket washer having sealing engagevnient with the hub casing.

2. In an idler of the kind including a pulley having a cylindrical hubcasing, a hollow shaft extending therethrough, an anti-friction bearingbetweenthe casing and the shaft at the inner end-of the casing and acollar secured to the shaft and extending from the bearing -to the outerend -of the' shaft, the improvement which comprises: an annular greaseseal element adjacent the outer end of the anti-friction bearing havingits outer periphery engaged with the hub casing for rotation therewith;a pair of spaced washer members' s'eeured t the collar with clearahee'between their Outer perpheries and the hub easing, the inner of saidwasher members lying adjacent Athe outer surface of Ithe grease sealelement; a second* annular grease seal element located between thewasher members with its outer periphery engaged with the hub casing frrotation therewith: and, n the outer Side of said washer members, anannular shell of inwardly' opening U-sectiori encircling but spaced fromthe collar and secured to the hub casing for rota; tion therewith .andan annular dust seal element clamped in said shell 'with its innerperiphery' engaging the collar.

3. In an idler of the kind including a 'puiiey having 4a cylindrical hubcasing, a hollow shaft extending therethrough, an anti-friction bearingbetween the casing anc the shaft at the inner ena of the casing and acollarsecured to the shaft and extending fromr the bearing to the outerend of the shaft, the improvement which comprises: an annular gre-aseseal element adjacent the outer end of the anti-friction bearing havingits outer periphery engaged with the hub casing for rotation therewith;apair of spaced washer ineinbers secured to the collar With clearancebetween their outer peripheriesand the hub casing, the inner of saidwasher members lying adjacent the outer surface of the grease sealelement; a second annular grease seal element located between the washermembers with its outer periphery engaged with the hub casing forrotationtherewith; 'and a gasket Washer encircling but spaced from the shaft onthe inner side ofthe bearing, the outer periphery of said gasket washerhaving sealing engagement with the hub casing.

XVILLIAM F. BANKAUF. WILLIAM E. HERRMANN. I-IARIILTON M. ROSS.

References cited in the sie of this patent' UNITED STATES PATENTS Number

